1. Field of the Invention
The present invention relates to systems for connecting telephone lines to computer networks, and more particularly to an architecture for providing a single system image across multiple network access servers, which connect telephone subscriber lines to a computer network.
2. Related Art
With the advent of computer networking and personal computers, telephone lines are increasingly being used to connect computer systems to computer networks such as the Internet. This has led to the development of network access servers for connecting telephone lines to computer networks. These networks access servers come in a number of forms.
Some network access servers include separate line servers and packet processors. Line servers connect to telephone lines and handle data communications across the telephone lines, for example handling modem scripts. Packet processors connect to a packet-switched network, such as the Internet, and coordinate communications across the packet-switched network. A packet processor makes decisions about whether a call can be accepted from a telephone line and how to forward the constituent data packets to the packet-switched network. Line servers and packet processors communicate with each other through a communication channel. Sometimes they use a tunneling protocol, such as the point to point tunneling protocol (PPTP) to communicate through the communication channel.
Other network access servers include a line server and a packet processor integrated together into a single module or box. The line server connects to telephone lines, and the packet processor connects to a packet-switched network. The line server and packet processor connect to each other through internal connections within the integrated module.
As telephone lines are being increasingly used to connect computers to computer networks, there is an increasing need for network access servers with larger numbers of ports to service larger numbers of telephone lines.
What is needed is a network access server architecture which can flexibly accommodate larger numbers of telephone lines.